- Introduction
- Exceptions to the predicted skin-color pattern
- Skin color and the migratory patterns of human populations
- Convincing explanation for the hairlessness of humans
- Reasons for thicker and longer hair in some areas
- Functions of skin
- Variety of skin color across the globe
- How touching premature babies can raise their survivorship
Introduction
Having dark skin (more melanin) improves the probability of not suffering from skin cancer ailments such as basal cancer. However, dark skin is very reactive to stimuli and may easily attract pimple, inflammation, and rash among others. The occurence of post inflammatory hyper pigmentation is more common in skin with more melanin than light skin. Light skin improves the chances of not suffering from skins bumps such as the acne keloidalis nuchae condition. However, light skin exposes the body to more ultraviolet rays that is known to cause skin ailments.
Exceptions to the predicted skin-color pattern
Polygenic inheritance is associated with unpredictable skin color. Thus, modification of the polygenic elements will eventually lead to an unpredictable skin color. Besides, migration from different regions has an impact on the skin color and various skin diseases.
Skin color and the migratory patterns of human populations
The dark skin color is predominant in the southern hemisphere of the globe while the light skin color is common in the northern hemisphere. The variation in skin color in these regions is related to the position of sunlight in each location. Dark skin is common in the southern hemisphere where the sun is hot and ultra violet radiation very intense.
Convincing explanation for the hairlessness of humans
The cooling theory is the most convincing explanation as to why human beings are hairless. According to this theory, the loss of hair was necessary to survive the hash and hot savannah climate. The loss of hair protected man from exposure to excess sun rays. Thus, hairlessness feature ensured that mankind was in a position to lose and radiate heat through convective cooling.
Reasons for thicker and longer hair in some areas
Mankind retained thicker and longer hair on some parts of the body such as the head, armpits, and pubic area to protect sensitive body organs against harsh weather. Besides, retention of thicker and longer hair defined sexuality and its ornamentation. In addition, longer and thicker hair in these parts would hide what mankind considered private, especially the sexual organ.
Functions of skin
The skin has a composite layer that offers protection against damage and pathogen from the external environment. It has active sensation nerve endings that facilitate involuntary reaction against slightest change in temperature, touch and bruises among others. The skin acts as a heat regulator through conduction, convection and radiation. It protects the body from dehydration through its thick and semi-impermeable barrier besides being a storage organ for water and lipids. In addition, the skin facilitates excretion of urea from the body through the sweat glands under the epidermis.
Variety of skin color across the globe
Jablonski offers explanation on the differences in skin color across the globe as contributed by location of mankind and weather (heat). For instance, people living in the northern hemisphere have light skin because of the low level of ultraviolet rays. However, people living in the southern hemisphere have dark skin since the level of ultraviolet rays is very concentrated per square area.
How touching premature babies can raise their survivorship
Touching a premature baby through stroking and gentle massage stimulates the sensitive skin to promote physical and psychological development. Through a regular and gentle touch, a premature baby is able to grow faster and gain weight within a short time since its body temperature is enhanced through the body contact.